1. Field of the Invention
The present invention relates to a pedestrian detection system for accurately detecting pedestrians to assist driver's driving effectively and a vehicle driving assist system with a pedestrian detection system.
2. Description of the Related Art
Various environment-recognition sensing techniques have been developed recently for application to vehicle driving assist system and, particularly, pedestrian detection has received attention. Collisions between pedestrians and vehicles often occur because of, for example a delay in recognizing pedestrians by drivers, doing significant harm to pedestrians. Accordingly, it is required to detect pedestrians as early as possible.
For example, Japanese Unexamined Patent Application Publication No. 2001-351193 discloses a technique for determining whether pedestrians are present from features of an image in an object region, acquired from an on-board stereo camera, such as object width, longitudinal dispersion, longitudinal barycenter, vertical integrated-value distribution.
However, the pedestrian determination technique disclosed in foregoing Japanese Unexamined Patent Application Publication No. 2001-351193 is a method for detecting pedestrians present in the image. Accordingly, also the pedestrians, who need not to be detected, may be detected, such as pedestrians at rest with little possibility of entering a vehicle traveling route. Also, it is a method whereby pedestrians are detected by calculating multiple features only after the entire body of the pedestrians is present in the image, thus having the problem of a delay in determination for pedestrians who enter from the exterior of the image. Furthermore, a load applied to the calculation unit is high, since multiple features are calculated, so that processes to be installed in the calculation unit, other than the pedestrian detection process, are limited and, more advanced and higher-speed image processing is precluded since frame intervals cannot be reduced.